HONOLULU — Some same-sex couples plan to get married as soon as they’re able to do so legally in Hawaii on Monday.

A ceremony for six couples at the Sheraton Waikiki is one of several wedding events taking place soon after 12:01 a.m., when a new law allows gay couples to marry in the state.

Couples who want to get married as early as possible on Monday won’t have to wait until Hawaii’s Health Department opens its doors at 8 a.m. Same-sex couples can begin applying for marriage licenses online at midnight, department spokeswoman Janice Okubo said. Okubo said the state’s marriage license application site will switch to add options for partners to identify themselves as bride and bride, groom and groom, or spouse and spouse.

The licenses can then be approved by any state-certified license agent around the state, Okubo said. The agents operate around the islands, including in resorts on Maui, the Big Island and Lanai. Okubo said the license agents make their own arrangements and can quickly approve licenses through the online system.

Hotels and wedding planners expect to benefit from an estimated $217 million tourism boost over the next three years with same-sex couples from other states seeking destination weddings.

The Sheraton’s midnight event shows that major hotels realize the business potential of the gay weddings market, said Honolulu Pride Chairman Michael Golojuch Jr., one of the event’s organizers. “If you don’t reach out to us, you’re turning away money,” he said. “We support companies that support us.”

He said that since the governor signed the gay marriage bill, he’s noticing ads from the wedding industry targeting the gay community. But he has yet to see any marketing efforts from the state’s tourism authority.

“If they see the Sheraton is willing to put this much time and money into this event, they’ll realize this is a market they want to go after,” he said.

After the bill signing, Hawaii Tourism Authority President and CEO Mike McCartney said the agency expects gay marriage to have a positive effect on tourism. “Hawaii is an ideal destination to celebrate marriage and romance, and we continue to welcome all couples that want to experience the Hawaiian Islands and embrace our unique people, place and culture,” he said.

For now, marketing efforts focus on regions and promoting the experience of a Hawaii vacation, an HTA spokeswoman said Friday.

Holding the midnight ceremony at the Sheraton and donating the event space is both the right thing to do and a good business move, said Kelly Sanders, area managing director for the Starwood Hotels and Resorts’ four Waikiki properties, including the Sheraton.

“I think overall marriage and weddings is a key part of what we do in Hawaii,” he said. “When you look at the GLBT market, the biggest thing is they need to know they’re welcome. Hawaii is an all-inclusive destination.”

Rev. Libby Kelson-Fulcher of Big Island wedding planning company, Weddings A La Heart, said she’s planning a Dec. 26 beachfront wedding for a lesbian couple from Salem, Ore., and is working on booking other gay weddings for January. “I have a feeling 2014 is really going to be a busy year,” she said. “I think this law is going to be an incredible boon for Hawaii.”

When Keola Akana and Ethan Wung are married at the Sheraton Monday, it will be more than a year after their 150-guest wedding. They threw a wedding for their civil union at an east Honolulu Episcopal church in July 2012.

“We didn’t get federal rights, only state rights,” he said. “We’re going to be attaining all the rights our federal government, our country, offers. It’s important that we mark this ... We’ll celebrate anniversaries for our July wedding and our December marriage.”